After 12 seasons and almost 300 episodes, it’s finally time to say goodbye to The Big Bang Theory. On Thursday night, the beloved CBS sitcom ended its historic run with an hourlong episode and farewell special, “Unraveling the Mystery: A Big Bang Farewell,” that showed just how far all these characters have come in their personal and professional journeys. The episode follows Sheldon (Jim Parson) and Amy (Mayim Bialik) as they win the Nobel Prize in physics and travel to Stockholm with their friends to celebrate, but that’s not the only thing the Big Bang Theory series finale had in store: viewers were also treated to a guest appearance from Buffy the Vampire Slayer‘s Sarah Michelle Gellar, a Leonard-Penny pregnancy, and more. Bazinga!

So, what did you miss on Big Bang Theory last night?

What happened on The Big Bang Theory series finale?

It was a big night for our core pals up in Stockholm. In the hourlong series finale, “The Change Constant/The Stockholm Syndrome,” Amy and Sheldon discover that they had earned a Nobel Prize in physics for their research, and the group accompanies them on their trip overseas to help celebrate. Bernadette (Melissa Rauch) and Wolowitz (Simon Helberg) are initially hesitant to leave their children, but they decide that the trip will be a much-needed opportunity to spend time with their friends.

On the plane, Penny and Leonard share that they are having a baby — some life-altering news that Sheldon, as per usual, couldn’t care less about. But later, while giving his acceptance speech, he comes around, and he dedicates the award to the friends who have loved and supported him for the last decade.

Yes, that was indeed Sarah Michelle Gellar. While on the flight to Stockholm, Sweden, Koothrappali (Kunal Nayyar) makes friends with his seat mate (or, as my friend once called it, a “plane partner”), who happens to be a woman who looks a lot like Sarah Michelle Gellar. The Buffy star later accompanies him to Sheldon and Amy’s Nobel Prize ceremony, but as she tells Koothrappali, “This isn’t a date.”

Photo: CBS

What happened on the Big Bang Theory farewell special “Unraveling the Mystery”?

After Young Sheldon ended (more on that later), CBS aired a Big Bang Theory farewell special titled “Unraveling the Mystery: A Big Bang Farewell.” Hosted by Johnny Galecki and Kaley Cuoco, the special featured behind-the-scenes clips, interviews, and highlights from the show’s twelve seasons. If you missed it — or if you just want to watch it again — you can stream Big Bang Theory “Unraveling the Mystery” on CBS.

How much Nobel Prize money did Sheldon and Amy win?

Sheldon’s Nobel Prize speech may have been all about his friends (it was very heartwarming), but let’s not forget that the award comes with a serious cash prize, as well. According to Thought Co, each Nobel laureate is awarded 8 million SEK, or about $1.1 million. That’s on top of the medal itself, which is made of pure gold and costs upwards of $10,000. It looks like Penny and Leonard’s baby is in for quite a baby shower gift.

Why did The Big Bang Theory end?

This one is simply a matter of time. After 12 years on CBS, it’s time for Big Bang Theory to come to an end. “There was no factor; there was no situation that I was like, ‘Well, I’ve had enough of that.’ No. There was nothing like that. It was just…when you know, you know,” star Jim Parsons told The Hollywood Reporter in early May. “And you’re susceptible and thrown around by the whims of your own existence and getting to a certain age and your life changes and suddenly you just think different.”

However, Parsons will stay in the Big Bang Theory family, as he does the voiceover for Young Sheldon. The spin-off series honored Big Bang Theory in its own way on Thursday night with a sweet bit about its characters eventually meeting: